opentelemetry: create a new module

caddyconfig/httpcaddyfile/directives.go

@@ -37,6 +37,8 @@ import (
 // The header directive goes second so that headers
 // can be manipulated before doing redirects.
 var directiveOrder = []string{
+	"opentelemetry",
+
 	"map",
 	"root",
 

caddytest/integration/caddyfile_adapt/opentelemetry.txt

@@ -0,0 +1,36 @@
+:80 {
+	opentelemetry /myhandler {
+        span_name my-span
+	}
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":80"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"path": [
+										"/myhandler"
+									]
+								}
+							],
+							"handle": [
+								{
+									"handler": "opentelemetry",
+									"span_name": "my-span"
+								}
+							]
+						}
+					]
+				}
+			}
+		}
+	}
+}

go.mod

@@ -24,11 +24,17 @@ require (
 	github.com/smallstep/truststore v0.9.6
 	github.com/yuin/goldmark v1.4.0
 	github.com/yuin/goldmark-highlighting v0.0.0-20210516132338-9216f9c5aa01
+	go.opentelemetry.io/otel v1.0.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.0.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.0.0
+	go.opentelemetry.io/otel/sdk v1.0.0
+	go.opentelemetry.io/otel/trace v1.0.0
 	go.uber.org/zap v1.19.0
 	golang.org/x/crypto v0.0.0-20210616213533-5ff15b29337e
 	golang.org/x/net v0.0.0-20210614182718-04defd469f4e
 	golang.org/x/term v0.0.0-20210503060354-a79de5458b56
 	google.golang.org/genproto v0.0.0-20210604141403-392c879c8b08
+	google.golang.org/grpc v1.40.0
 	google.golang.org/protobuf v1.27.1
 	gopkg.in/natefinch/lumberjack.v2 v2.0.0
 	gopkg.in/yaml.v2 v2.4.0

go.sum

@@ -178,7 +178,10 @@ github.com/caddyserver/certmagic v0.14.5/go.mod h1:/0VQ5og2Jxa5yBQ8eT80wWS7fi/Dg
 github.com/campoy/unique v0.0.0-20180121183637-88950e537e7e/go.mod h1:9IOqJGCPMSc6E5ydlp5NIonxObaeu/Iub/X03EKPVYo=
 github.com/casbin/casbin/v2 v2.1.2/go.mod h1:YcPU1XXisHhLzuxH9coDNf2FbKpjGlbCg3n9yuLkIJQ=
 github.com/cavaliercoder/go-cpio v0.0.0-20180626203310-925f9528c45e/go.mod h1:oDpT4efm8tSYHXV5tHSdRvBet/b/QzxZ+XyyPehvm3A=
+github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
 github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
+github.com/cenkalti/backoff/v4 v4.1.1 h1:G2HAfAmvm/GcKan2oOQpBXOd2tT2G57ZnZGWa1PxPBQ=
+github.com/cenkalti/backoff/v4 v4.1.1/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
 github.com/census-instrumentation/opencensus-proto v0.2.0/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/census-instrumentation/opencensus-proto v0.3.0/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
@@ -201,6 +204,7 @@ github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDk
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/cncf/udpa/go v0.0.0-20200629203442-efcf912fb354/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
+github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cockroachdb/datadriven v0.0.0-20190809214429-80d97fb3cbaa/go.mod h1:zn76sxSg3SzpJ0PPJaLDCu+Bu0Lg3sKTORVIj19EIF8=
 github.com/cockroachdb/datadriven v0.0.0-20200714090401-bf6692d28da5/go.mod h1:h6jFvWxBdQXxjopDMZyH2UVceIRfR84bdzbkoKrsWNo=
 github.com/cockroachdb/errors v1.2.4/go.mod h1:rQD95gz6FARkaKkQXUksEje/d9a6wBJoCr5oaCLELYA=
@@ -271,6 +275,7 @@ github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1m
 github.com/envoyproxy/go-control-plane v0.9.7/go.mod h1:cwu0lG7PUMfa9snN8LXBig5ynNVH9qI8YYLbd1fK2po=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0/go.mod h1:hliV/p42l8fGbc6Y9bQ70uLwIvmJyVE5k4iMKlh8wCQ=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/envoyproxy/protoc-gen-validate v0.3.0-java/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/etcd-io/gofail v0.0.0-20190801230047-ad7f989257ca/go.mod h1:49H/RkXP8pKaZy4h0d+NW16rSLhyVBt4o6VLJbmOqDE=
@@ -468,6 +473,7 @@ github.com/grpc-ecosystem/grpc-gateway v1.9.0/go.mod h1:vNeuVxBJEsws4ogUvrchl83t
 github.com/grpc-ecosystem/grpc-gateway v1.9.2/go.mod h1:vNeuVxBJEsws4ogUvrchl83t/GYV9WGTSLVdBhOQFDY=
 github.com/grpc-ecosystem/grpc-gateway v1.9.5/go.mod h1:vNeuVxBJEsws4ogUvrchl83t/GYV9WGTSLVdBhOQFDY=
 github.com/grpc-ecosystem/grpc-gateway v1.14.6/go.mod h1:zdiPV4Yse/1gnckTHtghG4GkDEdKCRJduHpTxT3/jcw=
+github.com/grpc-ecosystem/grpc-gateway v1.16.0 h1:gmcG1KaJ57LophUzW0Hy8NmPhnMZb4M0+kPpLofRdBo=
 github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/hashicorp/consul/api v1.1.0/go.mod h1:VmuI/Lkw1nC05EYQWNKwWGbkg+FbDBtguAZLlVdkD9Q=
 github.com/hashicorp/consul/api v1.3.0/go.mod h1:MmDNSzIMUjNpY/mQ398R4bk2FnqQLoPndWW5VkKPlCE=
@@ -973,14 +979,27 @@ go.opencensus.io v0.23.0/go.mod h1:XItmlyltB5F7CS4xOC1DcqMoFqwtC6OG2xF7mCv7P7E=
 go.opentelemetry.io/contrib v0.20.0/go.mod h1:G/EtFaa6qaN7+LxqfIAT3GiZa7Wv5DTBUzl5H4LY0Kc=
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.20.0/go.mod h1:oVGt1LRbBOBq1A5BQLlUg9UaU/54aiHw8cgjV3aWZ/E=
 go.opentelemetry.io/otel v0.20.0/go.mod h1:Y3ugLH2oa81t5QO+Lty+zXf8zC9L26ax4Nzoxm/dooo=
+go.opentelemetry.io/otel v1.0.0 h1:qTTn6x71GVBvoafHK/yaRUmFzI4LcONZD0/kXxl5PHI=
+go.opentelemetry.io/otel v1.0.0/go.mod h1:AjRVh9A5/5DE7S+mZtTR6t8vpKKryam+0lREnfmS4cg=
+go.opentelemetry.io/otel/exporters/otlp v0.20.0 h1:PTNgq9MRmQqqJY0REVbZFvwkYOA85vbdQU/nVfxDyqg=
 go.opentelemetry.io/otel/exporters/otlp v0.20.0/go.mod h1:YIieizyaN77rtLJra0buKiNBOm9XQfkPEKBeuhoMwAM=
+go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.0.0 h1:Vv4wbLEjheCTPV07jEav7fyUpJkyftQK7Ss2G7qgdSo=
+go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.0.0/go.mod h1:3VqVbIbjAycfL1C7sIu/Uh/kACIUPWHztt8ODYwR3oM=
+go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.0.0 h1:B9VtEB1u41Ohnl8U6rMCh1jjedu8HwFh4D0QeB+1N+0=
+go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.0.0/go.mod h1:zhEt6O5GGJ3NCAICr4hlCPoDb2GQuh4Obb4gZBgkoQQ=
 go.opentelemetry.io/otel/metric v0.20.0/go.mod h1:598I5tYlH1vzBjn+BTuhzTCSb/9debfNp6R3s7Pr1eU=
 go.opentelemetry.io/otel/oteltest v0.20.0/go.mod h1:L7bgKf9ZB7qCwT9Up7i9/pn0PWIa9FqQ2IQ8LoxiGnw=
 go.opentelemetry.io/otel/sdk v0.20.0/go.mod h1:g/IcepuwNsoiX5Byy2nNV0ySUF1em498m7hBWC279Yc=
+go.opentelemetry.io/otel/sdk v1.0.0 h1:BNPMYUONPNbLneMttKSjQhOTlFLOD9U22HNG1KrIN2Y=
+go.opentelemetry.io/otel/sdk v1.0.0/go.mod h1:PCrDHlSy5x1kjezSdL37PhbFUMjrsLRshJ2zCzeXwbM=
 go.opentelemetry.io/otel/sdk/export/metric v0.20.0/go.mod h1:h7RBNMsDJ5pmI1zExLi+bJK+Dr8NQCh0qGhm1KDnNlE=
 go.opentelemetry.io/otel/sdk/metric v0.20.0/go.mod h1:knxiS8Xd4E/N+ZqKmUPf3gTTZ4/0TjTXukfxjzSTpHE=
 go.opentelemetry.io/otel/trace v0.20.0/go.mod h1:6GjCW8zgDjwGHGa6GkyeB8+/5vjT16gUEi0Nf1iBdgw=
+go.opentelemetry.io/otel/trace v1.0.0 h1:TSBr8GTEtKevYMG/2d21M989r5WJYVimhTHBKVEZuh4=
+go.opentelemetry.io/otel/trace v1.0.0/go.mod h1:PXTWqayeFUlJV1YDNhsJYB184+IvAH814St6o6ajzIs=
 go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqeYNgFYFoEGnI=
+go.opentelemetry.io/proto/otlp v0.9.0 h1:C0g6TWmQYvjKRnljRULLWUVJGy8Uvu0NEL/5frY2/t4=
+go.opentelemetry.io/proto/otlp v0.9.0/go.mod h1:1vKfU9rv61e9EVGthD1zNvUbiwPcimSsOPU9brfSHJg=
 go.step.sm/cli-utils v0.4.1 h1:QztRUhGYjOPM1I2Nmi7V6XejQyVtcESmo+sbegxvX7Q=
 go.step.sm/cli-utils v0.4.1/go.mod h1:hWYVOSlw8W9Pd+BwIbs/aftVVMRms3EG7Q2qLRwc0WA=
 go.step.sm/crypto v0.9.0 h1:q2AllTSnVj4NRtyEPkGW2ohArLmbGbe6ZAL/VIOKDzA=
@@ -1247,6 +1266,7 @@ golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210403161142-5e06dd20ab57/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210412220455-f1c623a9e750/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423185535-09eb48e85fd7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210503080704-8803ae5d1324/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210514084401-e8d321eab015/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -1486,8 +1506,9 @@ google.golang.org/grpc v1.36.0/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAG
 google.golang.org/grpc v1.36.1/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
 google.golang.org/grpc v1.37.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
 google.golang.org/grpc v1.37.1/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
-google.golang.org/grpc v1.38.0 h1:/9BgsAsa5nWe26HqOlvlgJnqBuktYOLCgjCPqsa56W0=
 google.golang.org/grpc v1.38.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
+google.golang.org/grpc v1.40.0 h1:AGJ0Ih4mHjSeibYkFGh1dD9KJ/eOtZ93I6hoHhukQ5Q=
+google.golang.org/grpc v1.40.0/go.mod h1:ogyxbiOoUXAkP+4+xa6PZSE9DZgIHtSpzjDTB9KAK34=
 google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.1.0/go.mod h1:6Kw0yEErY5E/yWrBtf03jp27GLLJujG4z/JK95pnjjw=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=

modules/caddyhttp/opentelemetry/README.md

@@ -0,0 +1,59 @@
+# OpenTelemetry module
+
+This module provides integration with OpenTelemetry tracing facilities. It is implemented
+as `caddyhttp.MiddlewareHandler` and can be chained into a list of other handlers.
+
+When enabled, it propagates an existing tracing context or will init a new one otherwise.
+
+It is based on `https://github.com/open-telemetry/opentelemetry-go`.
+
+## Configuration
+
+### Environment variables
+
+It can be configured using the environment variables defined
+by the [OpenTelemetry Environment Variable Specification](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md).
+
+IMPORTANT: Please, consider the version
+of [https://github.com/open-telemetry/opentelemetry-go](https://github.com/open-telemetry/opentelemetry-go). Some parts
+of the specification may be not implemented yet.
+
+Required by module environment variables are: OTEL_EXPORTER_OTLP_PROTOCOL/OTEL_EXPORTER_OTLP_TRACES_PROTOCOL and
+OTEL_PROPAGATORS.
+
+If neither OTEL_EXPORTER_OTLP_INSECURE nor OTEL_EXPORTER_OTLP_SPAN_INSECURE is provided, then:
+
+1. If OTEL_EXPORTER_OTLP_CERTIFICATE or OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE are specified they will be used for TLS.
+2. Else if both OTEL_EXPORTER_OTLP_CERTIFICATE and OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE are not specified, then default
+   TLS with the default `tls.Config` config will be used for an exporter.
+
+For the exporter configuration details, please
+see [spec](https://github.com/open-telemetry/opentelemetry-specification/blob/a4440931b522c7351b0485ff4899f786b4ff4459/specification/protocol/exporter.md)
+.
+
+Example:
+
+```bash
+export OTEL_EXPORTER_OTLP_HEADERS="myAuthHeader=myToken"
+export OTEL_EXPORTER_OTLP_PROTOCOL=grpc
+export OTEL_PROPAGATORS=tracecontext,baggage
+export OTEL_EXPORTER_OTLP_SPAN_INSECURE=false
+export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=localhost:12345
+```
+
+### Caddy file configuration
+
+Here is an example of **Caddyfile**:
+
+```
+handle /myHanlder {
+    opentelemetry {
+            span_name my-span
+    }       
+    reverse_proxy 127.0.0.1:8081
+}
+```
+
+Please check span
+naming [guideline](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#span)
+.

modules/caddyhttp/opentelemetry/module.go

@@ -0,0 +1,123 @@
+package opentelemetry
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
+	"go.uber.org/zap"
+)
+
+func init() {
+	caddy.RegisterModule(OpenTelemetry{})
+	httpcaddyfile.RegisterHandlerDirective("opentelemetry", parseCaddyfile)
+}
+
+// OpenTelemetry implements an HTTP handler that adds support for the opentelemetry tracing.
+// It is responsible for the injection and propagation of the tracing contexts.
+// OpenTelemetry module can be configured via environment variables https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md. Some values can be overwritten with values from the configuration file.
+type OpenTelemetry struct {
+	// SpanName is a span name. It SHOULD follow the naming guideline https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#span
+	SpanName string `json:"span_name"`
+
+	// otel implements opentelemetry related logic.
+	otel openTelemetryWrapper
+
+	logger *zap.Logger
+}
+
+// CaddyModule returns the Caddy module information.
+func (OpenTelemetry) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		ID:  "http.handlers.opentelemetry",
+		New: func() caddy.Module { return new(OpenTelemetry) },
+	}
+}
+
+// Provision implements caddy.Provisioner.
+func (ot *OpenTelemetry) Provision(ctx caddy.Context) error {
+	ot.logger = ctx.Logger(ot)
+
+	var err error
+	ot.otel, err = newOpenTelemetryWrapper(ctx, ot.SpanName)
+
+	return err
+}
+
+// Cleanup implements caddy.CleanerUpper and closes any idle connections. It calls Shutdown method for a trace provider https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/sdk.md#shutdown.
+func (ot *OpenTelemetry) Cleanup() error {
+	if err := ot.otel.cleanup(ot.logger); err != nil {
+		return fmt.Errorf("tracerProvider shutdown: %w", err)
+	}
+	return nil
+}
+
+// Validate implements caddy.Validator.
+func (ot *OpenTelemetry) Validate() error {
+	if ot.otel.tracer == nil {
+		return errors.New("openTelemetry tracer is nil")
+	}
+
+	return nil
+}
+
+// ServeHTTP implements caddyhttp.MiddlewareHandler.
+func (ot *OpenTelemetry) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
+	return ot.otel.ServeHTTP(w, r, next)
+}
+
+// UnmarshalCaddyfile sets up the module from Caddyfile tokens.
+func (ot *OpenTelemetry) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	setParameter := func(d *caddyfile.Dispenser, val *string) error {
+		if d.NextArg() {
+			*val = d.Val()
+		} else {
+			return d.ArgErr()
+		}
+		if d.NextArg() {
+			return d.ArgErr()
+		}
+		return nil
+	}
+
+	// paramsMap is a mapping between "string" parameter from the Caddyfile and its destination within the module
+	paramsMap := map[string]*string{
+		"span_name": &ot.SpanName,
+	}
+
+	for d.Next() {
+		args := d.RemainingArgs()
+		if len(args) > 0 {
+			return d.ArgErr()
+		}
+
+		for d.NextBlock(0) {
+			if dst, ok := paramsMap[d.Val()]; ok {
+				if err := setParameter(d, dst); err != nil {
+					return err
+				}
+			} else {
+				return d.ArgErr()
+			}
+		}
+	}
+	return nil
+}
+
+func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
+	var m OpenTelemetry
+	err := m.UnmarshalCaddyfile(h.Dispenser)
+	return &m, err
+}
+
+// Interface guards
+var (
+	_ caddy.Provisioner           = (*OpenTelemetry)(nil)
+	_ caddy.Validator             = (*OpenTelemetry)(nil)
+	_ caddyhttp.MiddlewareHandler = (*OpenTelemetry)(nil)
+	_ caddyfile.Unmarshaler       = (*OpenTelemetry)(nil)
+)